i just realized that since big hero 6 takes place in 2032, if it was real hiro's parents just recently died or would soon because they died when he was 3 and he would be turning 4 in 2022
let's not think about the 2019-2022 pandemic going on
let's not think about how such a pandemic causing his parents' death would make Tadashi grow up to want to provide better free universal healthcare and lead him to majoring in engineering to create a "personal healthcare companion"
let's not think about how Cass relies on her cafe to provide for her family and that maybe she was so unwilling to close was because there was a time when it had to be closed and it was difficult to take care of a 3 year old and 10 year old
let's not think about how they are canonically a low-income partially poc family (reasoning: hiro received a full grant instead of full scholarship (honestly he probably got both and used the scholarship money for his projects); grants are for low income students.)
Dash thought it'll be a breeze looking out for Vanellope, as Jack Jack was the most handful kid to babysit. Besides, she's 17, why would Hiro even ask him to lookout for a 17 year old?